Wear-resistant air pump

ABSTRACT

A wear-resistant air pump includes a cylinder, a piston and rod set inserted in the cylinder and movable back and forth between two opposite ends of the cylinder, an air nozzle head located at one end of the piston and rod set outside the cylinder and opposite to the piston of the piston and rod set and adapted for connection to an air valve of an inflatable object, and a wear-resistant structure provided between the piston and the cylinder for bearing a relative reciprocating motion between the piston and the cylinder to prolong the lifespan of the air pump.

BACKGROUND OF THE INVENTION

1. Field of the Invention:

The present invention relates to air pump technology and more particularly, to a wear-resistant air pump that is durable in use.

2. Description of the Related Art:

In addition to the usage for personal transport and travel, bicycle is also intensively used by people for sport and recreational activities. Bikes can be classified into mountain bikes, road bikes or city bikes. When riding any type of bike, comfort and smoothness are the most important factors to be considered. These two factors depend upon the tire pressure. Therefore, before riding a bike, the tires of the bike must be properly inflated with an air pump.

A regular air pump generally comprises a cylinder, an air nozzle head located at one end of the cylinder and connectable to an air valve of an inflatable object, a piston accommodated in the cylinder, a piston rod connected to the piston and movable to reciprocate the piston relative to the cylinder. When operating the piston rod to reciprocate the piston relative to the cylinder, the piston is being continuously rubbed against the inside wall of the cylinder, causing generation of a high temperature, and the cylinder wall may be caused to deform by the high temperature. One the cylinder wall is deformed, the airtight status between the cylinder and the piston may be affected, leading to an air leakage to lower the air pumping performance and affect the lifespan of the air pump.

SUMMARY OF THE INVENTION

The present invention has been accomplished under the circumstances in view. It is therefore the main object of the present invention to prove a wear-resistant air pump, which has a wear-resistant structure provided between the piston and the cylinder, enhancing the wear-resistant ability of the air pump and prolonging the air pump lifespan.

To achieve this and other objects of the present invention, a wear-resistant air pump comprises a cylinder, a piston and rod set, an air nozzle head, and a wear-resistant structure. The piston and rod set is inserted into the cylinder, and movable back and forth between two opposite ends of the cylinder. Further, the piston and rod set comprises a piston slidably accommodated in the cylinder. The air nozzle head is located at one end of the cylinder and connectable to an air valve of an inflatable object. The wear-resistant structure is provided between the piston and the cylinder to bear a relative reciprocating motion between the piston and the cylinder, enhancing the wear-resistant ability of the cylinder and prolonging the cylinder lifespan.

Other advantages and features of the present invention will be fully understood by reference to the following specification in conjunction with the accompanying drawings, in which like reference signs denote like components of structure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational view of a wear-resistant air pump in accordance with the present invention.

FIG. 2 is an exploded view of the wear-resistant air pump in accordance with the present invention.

FIG. 3 is a longitudinal sectional view of the wear-resistant air pump in accordance with the present invention.

FIG. 4 is a schematic operational view of the present invention, illustrating the handle moved in direction away from the cylinder.

FIG. 5 is a schematic operational view of the present invention, illustrating the handle moved toward the cylinder.

FIG. 6 is an enlarged view of a part of FIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1-3, a wear-resistant air pump in accordance with the present invention is shown. The wear-resistant air pump 100 comprises a cylinder 10, a piston and rod set 20, an air nozzle head 30, and a wear-resistant structure 40.

The cylinder 10 is made from aluminum, comprising an air chamber 11 defined in between opposing first and second ends thereof, a thread, for example, outer thread 12 located at the second end, and an end cap, for example, internally threaded end cap 13 threaded onto the outer thread 12. The end cap 13 defines therein a through hole 14.

The piston and rod set 20 is inserted through the through hole 14 of the end cap 13 and set in the cylinder 10, and axially movable between the opposing first and second ends of the cylinder 10. Further, the piston and rod set 20 comprises a piston rod 21, a piston 22 located at one end of the piston rod 21, a handle 23 located at an opposite end of the piston rod 21. According to the present preferred embodiment, the handle 23 is detachably fastened to the opposite end of the piston rod 21 by a screw joint (not shown). Further, the piston 22 comprises a locating groove 221 extending around the periphery thereof, an O-ring 222 mounted in the locating groove 221, and a plurality of end notches 223 located at a front end thereof opposite to the piston rod 21 and equiangularly spaced around the periphery thereof.

The air nozzle head 30 is located at the first end of the cylinder 10, defining therein a transversely extending inside chamber 31, a vertical air hole 15 in communication between the transversely extending chamber 31 and the air chamber 11 in the cylinder 10, and a connection port 32 located at one end, namely, the front end thereof in communication with the transversely extending chamber 31 and connectable to an air valve of an inflatable object, for example bicycle tire (not shown). Further, the air nozzle head 30 is equipped with a sliding valve block 34 that is slidably mounted in the transversely extending chamber 31, and a lever 33 that is pivotally connected to an opposite end of the air nozzle head 30, i.e., the rear end of the air nozzle head 30 and biasable to move the sliding valve block 34 back and forth in the transversely extending chamber 31 between an open position where an angled air passage 341 defined in the sliding valve block 34 is kept in communication between the air hole 15 and the transversely extending chamber 31 for guiding compressed gas from the air chamber 11 in the cylinder 10 through the air hole 15 and the e transversely extending chamber 31 into the connected air valve of the external inflatable object (for example, bicycle tire), and a close position where the angled air passage 341 is kept away from the air hole 15 and the air hole 15 is blocked by the periphery of the sliding valve block 34.

The wear-resistant structure 40 is provided between the periphery of the piston 22 and the inside wall of the cylinder 10. According to the present preferred embodiment, the wear-resistant structure 40 is provided at the inside wall of the cylinder 10 and constantly kept in contact with the piston 22. Preferably, the wear-resistant structure 40 is a ceramic coating coated on the inside wall of the cylinder 10. For the advantages of high hardness and high wear resistance, the wear-resistant structure (ceramic coating) 40 enhances the durability of the inside wall of the cylinder 10, preventing cylinder damage or thermal deformation of the cylinder 10 due to reciprocating motion of the piston 22 relative to the cylinder 10 and generation of heat during reciprocation of the piston 22, and thus, the lifespan of the air pump 100 is greatly prolonged. Alternatively, the wear-resistant structure 40 can be an enamel coating coated on the inside wall of the cylinder 10.

Referring to FIGS. 4 and 5, during operation of the air pump 100, pull the handle 23 in direction away from the cylinder 10 to carry the piston rod 21 out of the cylinder 10, enabling outside air to enter the air chamber 11 in the cylinder 10 via the through hole 14 of the end cap 13. At this time, the O-ring 222 can be stopped at one end of each of the end notches 223, allowing the intake air to flow through the locating groove 221, the end notches 223 into the air chamber 11 into the front end of the air chamber 11. Thereafter, attach the connection port 32 of the air nozzle head 30 to the air valve of the inflatable object (bicycle tire) 200, and then bias the lever 33 to move the sliding block 34 to the open position where the angled air passage 341 is kept in communication between the air hole 15 and the transversely extending chamber 31, and then push the handle 23 to move the piston rod 21 toward the inside of the cylinder 10. At this time, the O-ring 222 can be stopped at one end of each of the locating groove 221 to keep the air chamber 11 in an airtight status, enabling the air in the air chamber 11 to be forced through the air hole 15, the air passage 341 and the transversely extending chamber 31 and the connection port 32 into the air valve of the inflatable object (bicycle tire) 200 to inflate the inflatable object (bicycle tire) 200.

FIG. 6 is an enlarged view of a part of FIG. 5. As illustrated, the wear-resistant structure 40 is located on the inside wall of the cylinder 10, enabling the piston 22 to be moved relative to the cylinder 10 without, deformation, avoiding air leakage. Further, the wear-resistant structure 40 can also be a hard film layer. This hard film layer can be a thin film of titanium nitride hard film layer. Further, the hard film layer can be formed on the inside wall of the cylinder 10 through a hard anodizing treatment, enhancing the wear-resistant ability of the cylinder 10.

In conclusion, the wear-resistant air pump has a wear-resistant structure provided between the piston and the cylinder to enhance the wear-resistant ability of the cylinder, avoiding cylinder deformation or damage, preventing air leakage, and prolonging the lifespan of the air pump. Further, the wear-resistant structure can be a ceramic coating, enamel coating or hard film layer coated on the inside wall of the cylinder.

Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims. 

What is claimed is:
 1. A wear-resistant air pump, comprising: a cylinder defining a first end and a second end opposite to said first end; a piston and rod set inserted in said cylinder and movable back and forth between said first end and said second end of said cylinder, said piston and rod set comprising a piston slidably fitted into the inside of said cylinder; an air nozzle head located at said first end of said cylinder and connectable to an air valve of an inflatable object; and a wear-resistant structure provided between said piston and said cylinder to bear a relative reciprocating motion between said piston and said cylinder.
 2. The wear-resistant air pump as claimed in claim 1, wherein said wear-resistant structure is a ceramic coating coated on the inside wall of said cylinder and kept in contact with said piston.
 3. The wear-resistant air pump as claimed in claim 1, wherein said wear-resistant structure is a hard film layer.
 4. The wear-resistant air pump as claimed in claim 3, wherein said hard film layer is a titanium nitride coating.
 5. The wear-resistant air pump as claimed in claim 1, wherein said hard film layer is coated on the inside wall of said cylinder and kept using a hard anodizing treatment.
 6. The wear-resistant air pump as claimed in claim. 1, wherein said hard film layer is an enamel coating.
 7. The wear-resistant air pump as claimed in claim 1, wherein said wear-resistant structure is coated on an inside wall of said cylinder and kept in contact with the periphery of said piston. 